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No Intelligent Aliens Detected In Gliese 581
astroengine writes "Using an Australian very long baseline array (VLBA) of three radio antennae, the first very long baseline interferometry (VLBI) campaign has been carried out on a SETI target star: the famous Gliese 581 red dwarf. However, after 8 hours of observing the star — thought to play host to six exoplanets, two of which are in the star's 'habitable zone' — no alien signals were detected. This result isn't surprising, as the likelihood of us stumbling across intelligent aliens living in the Gliese 581 system transmitting radio is extremely slim, but it does validate VLBI as a very exciting means of using the vast amount of exoplanetary data (coming from missions such as the Kepler space telescope) for 'directed SETI' projects."
If they're not smarter, better, or more civilized than we are, why would we want to meet them? Dealing with all the idiots here is more than enough, I don't want to have to deal with alien idiots too.
make imaginary.friends COUNT=100 VISIBLE=false
That's not quite true. Some of our signals are spread spectrum, but the vast majority of licensed bands are still the age old single peak and often at insane output powers. These are very easy to distinguish from background noise, and as often is the case you could simply apply a 25kHz bandwidth and pick one of a few common coding methods and listen right in. The actual use of encryption for radio communication is rare when you're looking at the entire spectrum used over a planet. Hell if you exclude WiFi and satellite TV it's incredibly rare when you look at any major city too.
On that note satellites have pointed dishes because they are incredibly weak. They have to be, it's not like we have power stations up there powering them. When talking to a satellite we're trying to pick out a whisper from an asthmatic across a noisy room. We attempt to make our ears highly directional and filter out other conversations and he in turn cups his mouth to get his little voice that bit higher. That's not what these SETI projects are looking for. They are looking for aliens who have set up multi-Gigawatt transmitters all over their planet, just like we have. The equivalent of a rave happening somewhere else in an otherwise quiet rural town.
Also the directionality equation incorporates both the receive and transmit paths. You could have a perfect unit gain transmitter sending power out equally in every direction and still pick it up line of sight from anywhere you want with a theoretical infinite gain receive antenna pointed in the right direction, providing there's no louder signal source in your frequency of interest in the way. VLBI which is what they are using here provides an incredibly amount of gain at the receive side. Lots of really good signal analysis from multiple dishes result in us using a theoretical dish with a size and gain that could not realistically be constructed.
Some real geniuses came up with these designs and I'm willing to bet they know their antenna theory enough to think that it would be possible to detect a sufficiently advanced civilisation who take a similar evolutionary route that we take.
This is true. Nearly all of what we have ever broadcast has been trashed into junk RF by the time it passes through our own heliopause. Voyager 1 and 2 are helping us learn that it is a fantastic filter aggressively scrubbing and sterilizing radio. Perhaps only a few terrifically strong military radar signals or intentional interplanetary signals (i.e. the powerful Arecibo transmissions) might have made it through. Decades of TV and radio have not. For practical purposes, our Sol system is silent. We are not emitting potent enough repeating signals of the sort we ourselves are seeking.
It is logical to expect a similar result for other planetary systems where something like a heliopause exists. RF would be trashed and never make it into interplanetary space.
For even more discouragement, remember that most of life on Earth does not use radio. A planet teeming with life might yet have nobody emitting even weak signals. Radio derives from the human need to communicate, constantly. Especially while driving. It is entirely possible that another similarly advanced species might not have that need to talk talk talk and entertain at a distance.
Anyway, the universe is a very big place. It's a long way down the road to the pharmacy, but that's nothing compared to the universe. Most of it is empty. On average, we don't actually exist at all. Sigh.
Sig for hire.